Arc-Shaped Polishing Pad for Localized Touch-Up
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Solution Overview
Problem
Chemical mechanical polishing (CMP) processes often result in non-uniformity and under-polished regions on substrates, particularly due to the limitations of bulk polishing methods that fail to address localized non-concentric and angular asymmetry issues.
Innovation Solution
A chemical mechanical polishing system employing a small polishing pad that undergoes orbital motion with a fixed angular orientation, utilizing a substrate support and drive system to maintain the pad in contact with a limited area of the substrate, ensuring precise control and uniformity through a combination of pressure-sensitive adhesives, clamps, and adjustable pressure chambers for optimal slurry transport and polishing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a bulk polishing method is used, then the entire substrate surface is polished, but non-uniformity and under-polished regions occur due to inability to address localized non-concentric and angular asymmetry issues
Solution Approach 1:
The polishing pad is segmented into different functional zones with distinct properties. The pad includes a polishing region with abrasive particles for material removal and a non-polishing region without abrasive particles that can be positioned over under-polished areas. This segmentation allows targeted polishing of specific substrate regions while avoiding over-polishing of already planarized areas, thereby resolving the contradiction between achieving uniformity and addressing localized issues.
Solution Approach 2:
Different regions of the polishing pad are assigned different local qualities - the polishing region has abrasive particles for active material removal, while the non-polishing region has no abrasive particles to prevent further removal. This local differentiation enables the system to adapt to localized substrate conditions, allowing precise control over which areas receive polishing action and which are left alone, thus improving both uniformity and localized adaptability.
2Manufacturing precision
If a polishing pad with limited contact area is used for touch-up polishing, then polishing uniformity is enhanced, but the device complexity increases due to orbital motion mechanism
Solution Approach 1:
The polishing pad integrates multiple functions into a single component: it combines the polishing function (abrasive region) with the positioning function (non-polishing region for alignment) and the motion control function (orbital path definition). By merging these functions into one pad structure, the system achieves precise polishing uniformity without requiring separate complex mechanisms for each function, thus reducing overall device complexity while maintaining high precision.
Solution Approach 2:
The polishing system employs dynamic orbital motion of the polishing pad relative to the substrate, replacing static or simple rotational motion. The orbital path allows the limited contact area of the polishing region to systematically cover the entire substrate surface over time, achieving uniform polishing across the substrate while using a smaller pad. This dynamic motion pattern enables precise control of material removal distribution without requiring a large, complex pad structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances polishing uniformity, reduces the risk of delamination, and improves the finish and flatness of substrates by allowing for targeted touch-up polishing, compensating for non-concentric uniformity and maintaining a consistent polishing rate across the substrate.
Implementation Method 1
utilizing a substrate support and drive system to maintain the pad in contact with a limited area of the substrate, ensuring precise control and uniformity through a combination of pressure-sensitive adhesives
Implementation Method 2
The drive system is configured to move the pad support and polishing pad in an orbital motion while the polishing pad is in contact with an upper surface of the substrate
Implementation Method 3
Chemical mechanical polishing (CMP) is one accepted method of planarization. This planarization method typically requires that the substrate be mounted on a carrier or polishing head. The exposed surface of the substrate is typically placed against a rotating polishing pad. An abrasive polishing slurry is typically supplied to the surface of the polishing pad.
Implementation Method 4
adjustable pressure chambers for optimal slurry transport and polishing efficiency
Data Source
AI summary
Chemical mechanical polishing can be used for “touch-up polishing” in which polishing is performed on a limited area of the front surface of the substrate. The contact area between the polishing pad and the substrate can be substantially smaller than the radius surface of the substrate. During polishing, the polishing pad can undergo an orbital motion. The polishing pad can be maintained in a fixed angular orientation during the orbital motion. The contact area can be arc-shaped. The contact area can be provided by one or more lower portions projecting downward from an upper portion of the polishing pad. A perimeter portion of the polishing pad can be vertically fixed to an annular member and a remainder of the polishing pad within the perimeter portion can be vertically free.